The present invention relates to press equipment with supporting apparatus for producing molding compound parts by compression.
Molding compound parts by compression have been made of molding compound materials which are fluidized to flow and fill a mold cavity. But, it is necessary to precisely move a moving platen of a press so as to maintain an upper mold half parallel to a lower mold half for producing parts with precise, even wall thickness. According to a permitted limit, the allowable gradient of the platen is from 0.1 mm to 0.15 mm per 3 meters of length or width. Therefore, conventional presses are needed with greatly increased stiffness in their frames, and high precision in order to move the platen as above described. However, it is not only uneconomical, but also difficult in practical application. Furthermore, in coating molded parts, the thickness of the coating film is usually required to be within about 0.1 mm to 0.15 mm, and it is desirable to coat the coating materials more thinner and more evenly on the molded parts.
The applicant has developed several methods and apparatus for producing molding compound parts by compression, for instance as shown in U.S. application Ser. No. 416,488 and Ser. No. 416,556, where the press equipment are provided with levelling devices at the four corners on the bed for supporting the platen so as to move parallel within the necessary stroke range. But, as shown in FIG. 1, the above levelling device 2 was composed of a position detector 4 such a linear scale, and the detector 4 was mounted on the upper portion of the supporting rod 6 like a cantilever.
Therefore, when the supporting rods 6 are inclined according to the clearance or abrasion of the sliding surface members 8, the positioning detectors 4 are inclined as shown in dotted lines, and the detecting error is greatly increased. In the above conventional methods and apparatus the levelling precision could not be raised, even if the precision of the position detectors could be raised. Thus, the conventional levelling precision has a limit.